Osteoarthritis(OA) is the number one source of disability among elderly persons. Frequently developing in the knee, OA often creates mobility restrictions contributing to a decrease in daily physical activity and muscular stress of the lower extremity. The natural adaptation of reduced muscular stress is disuse atrophy. We hypothesize that inactivity coupled with reduction in muscle recruitment during walking contributes to quadriceps weakness. Patients with OA will have weaker quadriceps muscles, lower daily step frequency, and lower quadriceps muscle recruitment when they walk. Testing included an isometric quadriceps muscle strength assessment, threedimensional gait analysis in conjuction with electromyography of the quadriceps muscle. Subjects also wore ankle stepcounter that tracked the number and frequency of steps. Three participants have completed testing: one TKA and two healthy participants. The person with OA was much weaker and was waking half as much as the healthy chohort. The OA subject also had lower average quadriceps musclerecruitment during gait. Thus far, our hypotheses are supported by our results, but more participants are needed to make meaningful conclusions.